Fermentation of <i>Bacillus thuringiensis</i> for exotoxin production: Process analysis study

Holmberg, Andrea; Sievänen, Risto; Carlberg, Gunnel

doi:10.1002/bit.260220812

Cited by 56 publications

(18 citation statements)

References 7 publications

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“…In agreement with the results of Holmberg et al (1980) and Holmberg and Ranta (1982), such a multiplicity of kinetic parameter estimates can be explained as a practical limitation (non-identifiability) of the Monod model, especially when the number of experimental data is limited and the substrate concentrations used are smaller by far than the saturation constant (Ks) of the Monod model. In the circumstances, such a model can be reduced to the following linear form:…”

Section: Cell Growth and Substrate Consumption Ratessupporting

confidence: 65%

Modelling of cyclic fed-batch plus batch polygalacturonase production by Aureobasidium pullulans on raw orange peel

Moresi

Petruccioli

Federici

1991

Appl Microbiol Biotechnol

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Cyclic fed-batch plus batch polygalacturonase production by Aureobasidium pullulans in slurry fermentation systems using raw orange peel as substrate was studied in a 3-dm 3~ stirred fermentor by setting the main operating variables ( T = 297 ° K; pHo = 3.2; OPo=3% w / v ; n = 7 0 0 r p m ) to optimal values determined previously. In this way, it was possible to stabilize enzyme excretion at 130-140 VU cm -3. The time course of this fermentation process in terms of cell growth, substrate consumption and enzyme synthesis was reconstructed with a mean standard error less than 10%, by applying an unstructured model set up in a batch run and further refined in a series of cyclic fedbatch plus batch operations. In particular, the enzyme formation rate was related to the effect of reducing sugars as inhibitors at higher concentrations and as activators at lower levels by using an exponential equation. Moreover, the consumption rate of reducing sugars was found to be linearly related to the cell growth rate, its specific rate being of pseudo-first order with respect to the reducing sugar concentration.orange peel to a previous set of operating conditions by submitting the main controlling parameters of this process to analysis according to the step-wise variation method. Whereas the overall cell growth appeared to be practically insensitive to any of the step changes of the control variables examined, polygalacturonase production was more sensitive to the initial pH value (pHo) and stirrer speed (n) than to fermentation temperature (7) and initial concentration of orange peel (OPo). In particular, the enzymatic activity was found to reach a maximum value of 110 VU cm-3 when T was varied in the range 291-300 ° K, and OP0, pHo and n were set to 2.5-3.0% w/v, 3.2 and 700 rpm, respectively (Petruccioli et al. 1990).The main aim of this work was to improve the prediction capability of an unstructured kinetic model previously developed by Petruccioli et al. (1990) to simulate experimental cell growth, enzyme production and substrate consumption in a laboratory-scale stirred fermentor under conventional batch a n d / o r cyclic fedbatch plus batch operations, and therefore provide a basis for further scale-up of the process.

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Section: Cell Growth and Substrate Consumption Ratessupporting

confidence: 65%

Modelling of cyclic fed-batch plus batch polygalacturonase production by Aureobasidium pullulans on raw orange peel

Moresi

Petruccioli

Federici

1991

Appl Microbiol Biotechnol

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“…kurstaki a maximum glucose concentration of 56 g/l can be utilized [2]. Holmberg and Sievanen [9] reported that high concentration of nutrients inhibit the growth of B. thuringiensis var. thuringiensis, harming the sporulation and toxin synthesis.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Bacillus thuringiensis var. israelensis growth on high glucose concentrations

Berbert-Molina

Prata

Pessanha

et al. 2008

J Ind Microbiol Biotechnol

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The kinetic and general growth features of Bacillus thuringiensis var. israelensis were evaluated. Initial glucose concentration (S0) in fermentation media varied from 10 to 152 g/l. The results afforded to characterize four morphologically and physiologically well-defined culture phases, independent of S0 values: Phase I, vegetative growth; Phase II, transition to sporulation; Phase III, sporulation; and Phase IV, spores maturation and cell lysis. Important process parameters were also determined. The maximum specific growth rates (microX,m) were not affected with S0 up to 75 g/l (1.0-1.1 per hour), but higher glucose concentrations resulted in growth inhibition by substrate, revealed by a reduction in microX,m values. These higher S0 values led to longer Phases III and IV and delayed sporulation. Similar biomass concentrations (Xm=15.2-15.9 g/l) were achieved with S0 over 30.8 g/l, with increasing residual substrate, suggesting a limitation in some other nutrients and the use of glucose to form other metabolites. In this case, with S0 from 30.8 to 152 g/l, cell yield (YX/S) decreased from 0.58 to 0.41 g/g. On the other hand, with S0=10 g/l growth was limited by substrate, and YX/S has shown its maximum value (0.83 g/g).

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“…Arcas et al (1984) reported that endotoxin levels of B. thuringiensis subsp. It is apparent that sporulation and toxin production of B. thuringiensis are inhibited when nutrient concentrations are too high (Holmberg et al 1980). Scherrer et al (1973), on the other hand, noted that maximum yields of subsp.…”

Section: Production Of Strain A12172 In Fermenter and Toxicity Of Thmentioning

confidence: 99%

Effect of Pheromone Permeation on Sustained Flight of Male Spruce Budworm

Sanders

1998

Can Entomol

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Fermentation of Bacillus thuringiensis for exotoxin production: Process analysis study

Cited by 56 publications

References 7 publications

Modelling of cyclic fed-batch plus batch polygalacturonase production by Aureobasidium pullulans on raw orange peel

Modelling of cyclic fed-batch plus batch polygalacturonase production by Aureobasidium pullulans on raw orange peel

Kinetics of Bacillus thuringiensis var. israelensis growth on high glucose concentrations

Effect of Pheromone Permeation on Sustained Flight of Male Spruce Budworm

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